1. Field of the Invention
The present invention relates generally to a white detecting method and an apparatus using the same. More particularly, the present invention relates to a white detecting method which is used in performing a white balancing, and an apparatus using the same.
2. Description of the Related Art
Generally, even though an imaging apparatus, such as a digital still camera, digital video camera or the like, photographs the same subject, an outward appearance of the color of the photographed subject is varied according to light sources of various conditions, such as solar light found outdoors, muted solar light as occurring on cloudy days, white color lamps as found indoors, fluorescent light, and so forth.
Also, the imaging apparatus faithfully responds to red (R), green (G), and blue (B), or (RGB) components included in the light sources, each of which has a different color temperature, so that it reproduces a blue-toned white if the color temperature is high and a red-toned white if the color temperature is low.
Accordingly, in such cases, there is a need for the blue-toned white and the red-toned white to be shown with pure white. Also, if the color temperature has been changed, it is preferable that a white balance is maintained at the changed color temperature. For this, in the case of an achromatic color subject, a ratio of RGB is controlled to be always maintained at a uniform value, or color difference signals R-Y and B-Y are controlled to be always maintained at zero. Performing such a function is called an adjustment of white balance or a white balancing.
To accurately perform the adjustment of white balance, there is a need to accurately detect a white which forms a reference. Such white detecting methods include one method which searches a luminance of the entire image, divides the searched luminance, receives data of B, R and G according to the respective divided luminances and then detects a most proximate white to a white area, and another method which divides an image into small windows, receives data of B, R and G, that is, color data, of the respective small windows, and then detects a white.
However, the method of using the luminance division may present a problem in that a high luminance of monochrome or the like is mixed in a color data detected as the white. In this case, if a color is corrected on the basis of the detected color data, an error probability is increased. Also, if a plurality of data of B, R and G having different ranges of luminance exist in an area adjacent to a luminance trace, the white is continuously varied, thereby resulting in an error during color correction and a small change in color sense.
Also, the method of using the window division may present a problem in that, since to perform the white balancing, a window most adjacent to a white trace is selected from among the large number of windows and this selected window is frequently changed, thus a minute change in color sense is frequently generated.
Accordingly, a need exists for a system and method for accurately detecting a white while also improving a stability of color sense and reducing an error probability.